Telephonic apparatuses to transmit and receive analog voice signals to and from a communication medium are well known. The transmission and reception of digital data signals to and from a communication medium has typically been accomplished by the use of a modem. A modem is a device which modulates the digital signal, i.e., converts the digital signal to an analog signal for transmission along the communication medium and demodulates or converts the analog signal received from the communication medium into a digital signal. The modem, in turn, is interfaced to a computer or other source of digital data. Various patents disclose or teach the use of a modem with a computer to transmit and to receive digital data signals to and from a communication medium. See, for example, U.S. Pat. Nos. 3,825,905; 4,040,014; 4,085,449 and 4,232,293.
U.S. Pat. No. 4,378,470 discloses an interface circuit for connection to non-dedicated telephone lines for a telephonic apparatus and a modem.
However, none of the prior art references discloses or teaches an apparatus in which the analog voice and digital data signals can be transmitted to and received from a communication medium in the same session. A session is a time period commencing when an originating party has placed a call to an answering party or parties, communicates with that party, and then terminates the call.
In the prior art, devices to detect various status tones or supervisory tones are known. Status tones are tones such as ringing tone, ring back tone, dial tone, busy tone, etc. Typically, these tones have been discriminated from one another on the basis of presence and duration of energy. For example, if the amount of energy present exceeds two seconds in duration, then it's probably a dial tone. A burst of energy not exceeding one-half second is a busy tone. This discrimination is contextual and is based upon a fixed threshhold. Further difficulty is that these tones are not always accurately held to a particular frequency.
There is also known in the prior art programmable electrical keys, i.e., switches whose functions can be set by a computer program. However, the problem of changing the labels of these programmed keys or of knowing what function has been programmed has not been addressed. To the extent that any labelling technique is known, it consists of simply affixing a tag or other designation to the associated key.